Soluble α-klotho is a potential biomarker associated with neuropsychiatric systemic lupus erythematosus

• Lower CSF α-Klotho levels appear to be associated with the endothelial dysfunction and neuronal damage in NPSLE patients.
• Our findings indicate that lower CSF α-Klotho levels, lower serum anti-Smith antibodies and higher serum C3 (mg/dL) are useful markers for predicting NPSLE.
• The determination of CSF α-Klotho levels may contribute to the diagnosis of NPSLE and may help elucidate the mechanisms underlying this disease.

A reduced level of the single-pass transmembrane protein α-Klotho is known to be associated with neuronal damage. We investigated whether α-Klotho in cerebrospinal fluid (CSF) could be a candidate marker for the diagnosis of neuropsychiatric systemic lupus erythematosus (NPSLE). We analyzed the laboratory data, symptoms and radiological image findings of 34 NPSLE patients. Patients with SLE without neuropsychiatric manifestations (SLE) (n = 25), and patients with viral meningitis (VM) (n = 19), multiple sclerosis (MS) (n = 20) or neuromyelitis optica (NMO) (n = 20) were included as controls. The multivariable analyses revealed that lower CSF α-Klotho level, lower serum anti-Smith antibodies (U/mL) and higher serum C3 (mg/dL) were significant factors for predicting NPSLE. The CSF α-Klotho levels of the NPSLE patients were inversely correlated with the level of granulocyte/macrophage-colony stimulating factor. Our data suggested that the determination of CSF α-Klotho levels will contribute to the diagnosis of NPSLE and help elucidate the mechanisms underlying this disease.